EP-A-1 089 470 discloses a set-top box that is connected to a television receiver through a video cable and an IEEE 1394 cable. A front end circuit extracts a broadcast signal corresponding to the station selection of a user from a DSS (Direct Satellite System) input from an antenna and outputs it to a descramble circuit. A charging circuit supplies the descramble circuit with the decoding key used for scramble release. A multiplex editing circuit rearranges the timestamp and packet length of an HD broadcast signal (which is MPEG encoded) from the descramble circuit into the structure of a transport stream defined in IEEE 1394 and then outputs it to an encryption circuit. When the broadcast signal concerned is pay per view, the encryption circuit encrypts the transport stream from the multiplex editing circuit. A controller controls a drive to read out a control program recorded in a magnetic disc, an optical disc, a magneto-optical disc or a semiconductor memory, and controls each circuit of the set top box on the basis of the control program thus read out and a command input from a user or the like. The charging circuit is not connected to the encryption circuit.
When the known terminal is employed, the entity transmitting data from the primary transmitter loses control the moment the data is decrypted in the primary terminal. Subsequently, even though the decrypted data is re-encrypted, this entity no longer controls access to the data. The operator of the primary terminal that is used to receive and re-transmit the data through the secondary network can determine which secondary receiver he will enable to decrypt the re-encrypted data stream, by sending them the key used to re-encrypt the data stream.